I am running Kubuntu 8.04 with a Geforce XFX 8600 GT 256MB / 540Mhz and a 1920x1200 pixel resolution screen. I use the 177.82 driver and the performance tweaks suggested on this site. 2D performance is generally acceptable but video playback is not very smooth, both for regular DVDs and especially for high definition video (MP2) files taken with my HD camcorder. Under Windows they play fine (I have a Q6600 2.4 Ghz quad core). Especially HD playback is not very smooth at all, lots of vertical banding appearing there. Is that supposed to be the best to expect from a 8600 GT under Linux?